The genome of the human immunodeficiency virus (HIV) encodes a protease that is responsible for the proteolytic processing of one or more polyprotein precursors such as the pol and gag gene products. HIV protease processes the gag precursor into core proteins and also processes the pol precursor into reverse transcriptase and protease.
The correct processing of the precursor polyproteins by HIV protease is necessary for the assembly of infectious virions. Therefore, inhibition of HIV protease provides a useful target for development of therapeutic agents for treatment of HIV infection.
In recent years, inhibitors of HIV protease have become an important class of therapeutic agents for inhibition and treatment of HIV infection in humans. HIV protease inhibitors are especially effective when administered in combination with other classes of HIV therapeutic agents, especially inhibitors of HIV reverse transcriptase, in “cocktails” of HIV therapeutic agents.
At the present time, the HIV protease inhibitors saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, lopinavir/ritonavir, fosamprenavir, and atazanavir have been approved in the U.S. for treatment of HIV infection. There is a continuing need for improved HIV protease inhibitors that are very potent, that have reduced side-effects and that are effective against resistant strains of HIV.